Silicon optical transceiver chip

Abstract

The invention, which relates to the technical field of the optical receiver, discloses a silicon optical transceiver chip comprising an oblique incidence grating coupler, a symmetrical bidirectional angle multimode interference coupler, a micro-ring modulator, a micro-ring filter, and a single-input photoelectric detector. Each oblique incidence grating coupler is composed of a grating area and a spot-size converter, a certain coupling inclination angle is adopted by a grating etching part through an optical fiber, optical signals are obliquely incident into a grating coupling area, the optical signals are converted into single-mode conditions through the spot-size converters and transmitted into an optical waveguide, and then the input and output functions of the optical signals are achieved. According to the invention, a plurality of micro-ring modulators are used for converting electric signals into optical signals for information transmission, and a receiving part is combined with a micro-ring filter to realize a secondary filtering function, so that the crosstalk problem between two adjacent optical information transmission channels can be reduced.

Description

Technical Field

[0001] The present invention specifically relates to the technical field of optical receivers, and in particular to a silicon optical transceiver chip. Background Art

[0002] With the rapid development of the Internet and big data, the demand for communication has increased dramatically. Traditional electrical interconnection technology has been unable to cope with it. Optical communication technology has become the key to improving communication capacity with its advantages of high bandwidth and low loss. Wavelength division multiplexing technology uses the characteristics of different wavelengths of light not interfering with each other to achieve parallel transmission of multi-wavelength channels in optical fibers, significantly improving communication capacity. Silicon-based integrated chips can be mass-produced and reduce costs due to their CMOS compatibility, and have great potential. However, as the core component of wavelength division multiplexing technology, although the commercial models of optical receivers have good performance, they are large in size, complex in packaging and high in cost, which limits their widespread application. The progress of silicon-based optoelectronics has promoted the research of optical receivers. Their compact structure and high integration have shown significant advantages in short-distance communications. In addition, optical transmitters face challenges in increasing capacity. Optoelectronic integration technology has promoted the development of dual-band transmitting devices, which have high integration, small size, low cost and stable performance. They can meet the needs of modern communications and are expected to play an important role in the field of high-speed and large-capacity communications in the future.

[0003] The optical receivers involved in most current chips have failed to effectively integrate the advantages of microring resonators, resulting in poor performance in wavelength division multiplexing applications, affecting the efficiency of high-speed data transmission. Although the patent mentions methods to reduce crosstalk, in actual applications, the problem of crosstalk between signals of different wavelengths still exists. This crosstalk will reduce the receiver's ability to decode signals, especially in high-density wavelength division multiplexing scenarios, where signal interference is more significant. Therefore, further research and development of improvement solutions is needed to address the deficiencies of existing designs and improve the compatibility and overall performance of optical communication systems. Summary of the invention

[0004] The purpose of the present invention is to provide a silicon photonic transceiver chip, which adopts a symmetrical bidirectional angle multimode interference coupler. This design can effectively improve the selection characteristics of optical signals and simultaneously realize the multiplexing and demultiplexing functions of the wavelength division multiplexing of the transceiver chip. By cascading the wavelength division multiplexing system with the micro-ring filter, the system not only achieves efficient integration, but also significantly reduces the crosstalk between optical signals during signal transmission. In addition, the transmitting end and the receiving end are simultaneously integrated in the same wavelength division multiplexing device, and there is extremely little signal crosstalk between the two, while the area of ​​the entire system is well reduced. In order to solve the technical problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A silicon optical transceiver chip, comprising an oblique-incidence grating coupler, a symmetrical bidirectional angle multimode interference coupler, a micro-ring modulator, a micro-ring filter, and a single-input photodetector; The plurality of oblique-incidence grating couplers are composed of a grating region and a mode spot converter. The grating etched portion is a portion where a light signal is obliquely incident into the grating coupling region through an optical fiber using a certain coupling inclination angle, and the light signal is converted into a single-mode condition through the multi-mode spot converter and transmitted into the optical waveguide, thereby realizing the input and output functions of the light signal. The symmetrical bidirectional angular multimode interference coupler is composed of multiple mode spot converters and a single multimode waveguide structure. The overall structure of the symmetrical bidirectional angular multimode interference coupler is formed by etching silicon to form a ridge waveguide, and the etched conical structure with a certain angle is symmetrically placed on both sides of the ridge waveguide according to certain design rules.

[0006] As a further technical solution of the present invention, the symmetrical bidirectional angle multimode interference coupler can perform wavelength division multiplexing demultiplexing / multiplexing functions of optical signals, and can simultaneously realize the wavelength division and combination functions of the optical transceiver chip. In the receiving part, it is combined with a micro-ring filter to realize the secondary filtering function, which can greatly reduce the crosstalk problem between two adjacent channels.

[0007] As a further technical solution of the present invention, the multiple micro-ring modulators and the multiple micro-ring filters are similar in structure and are composed of a linear optical waveguide and a micro-ring resonant cavity. The micro-ring resonant cavity is usually a small circle or ellipse and can form an optical resonance effect.

[0008] As a further technical solution of the present invention, the micro-ring modulator is connected through the through end of the device, and the ring resonator of the micro-ring modulator has a PN carrier doping structure, the purpose of which is to adjust the effective refractive index and group refractive index in the waveguide by adding voltage to achieve the phase modulation effect of the optical signal.

[0009] As a further technical solution of the present invention, the micro-ring modulator is connected to the download end of the micro-ring filter to achieve a filtering effect, and is cascaded with the angle multi-mode interference coupler to achieve a secondary filtering function, which can greatly reduce the crosstalk between two adjacent information channels, and finally connect multiple single-input photodetectors for photoelectric conversion to achieve the optical information receiving function.

[0010] As a further technical solution of the present invention, R and T represent the wavelength of the receiving end and the wavelength of the transmitting end of the transceiver chip respectively, and the receiving end is input by multiple wavelengths of λ1, λ2, λ3, and λ4 respectively, and is input into the multimode waveguide region through a single-port pattern spot converter with an inclined angle of an angle multimode interference coupler, and wavelength division is performed according to the dispersion self-image principle of the multimode waveguide region, and the pattern spot converter at an oblique angle is output to achieve filtering; At the receiving end, multiple mode spot converters with tilted angles are input into the multimode waveguide area, multiplexed through the multimode waveguide area, and then output by a single oblique-incidence mode spot converter at the diagonal angle. The optical signals at the receiving and transmitting ends are transmitted through the same bidirectional symmetrical angle multimode interference coupler, which not only improves the information transmission efficiency, but also greatly reduces the overall layout area of ​​the system.

[0011] As a further technical solution of the present invention, the microring modulator includes a microring resonator, input and output waveguides and electrodes. The microring resonator is ring-shaped and has specific resonance characteristics. When an optical signal enters the microring through the input waveguide, if the wavelength of the optical signal matches the resonance wavelength of the microring, the signal of the wavelength will be enhanced. The modulation part has P+ and N+ carrier doping to form a PN node. By applying voltage to the electrode, the effective refractive index of the microring can be changed, thereby modulating the intensity of the output signal.

[0012] As a further technical solution of the present invention, a microring filter is mainly used to selectively filter optical signals of a specific wavelength. Its structure is similar to that of a microring modulator, but it usually does not include electrodes. The microring filter relies on resonance phenomenon and coupling design to achieve selective transmission of a specific wavelength by adjusting the shape, size or coupling mode of the microring. When the input optical signal passes through the microring, only the light that matches the resonant wavelength of the microring can pass through the output waveguide, while light of other wavelengths is suppressed. The microring filter structure has optical waveguides on the top and bottom, which are the through end and the download end respectively. The waveguide connected to the symmetrical bidirectional angle multimode interference coupler at one end is used as the through end, and the other end is the download end, which is connected to a single input photodetector for photoelectric conversion.

[0013] As a further technical solution of the present invention, the single-input photodetector is composed of a silicon-based single-mode optical waveguide and a conical mode spot converter on the left, with a wider ridge waveguide sandwiched in the middle. A layer of germanium waveguide is grown on the ridge waveguide, and P+ and N+ are doped on the germanium waveguide with an interval of Wi width. Metal G and S metal electrodes are respectively made in the doping area. The intrinsic region width Wi of the lateral pin structure can be adjusted by controlling the spacing between P+ and N+, and the speed of the single-input photodetector can be adjusted to the maximum by optimizing Wi.

[0014] As a further technical solution of the present invention, the microring modulator and the microring filter mainly involve the transmission spectrum change of the microring resonant cavity, and the transmittance T can be expressed as:

[0015] Where t is the coupling coefficient between the optical waveguide and the microring, β is the propagation constant of light in the microring, which is related to the wavelength λ. When the voltage V is applied, the refractive index n of the microring will change, causing the propagation constant β to change. Specifically, the change in refractive index can be expressed as: in is the refractive index of the material and V is the applied voltage:

[0016] This change will cause the resonant wavelength Offset occurs:

[0017] This wavelength shift will cause the transmission spectrum of the microring modulator to change, thereby achieving modulation of the optical signal. Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a plurality of oblique-incidence grating couplers to couple input and output of optical signals, and the oblique-incidence grating couplers are made of silicon-based materials, and can cooperate with a symmetrical bidirectional angle multimode interference coupler to perform wavelength division multiplexing demultiplexing / multiplexing functions of optical signals, and further can simultaneously realize the wave division and wave combination functions of an optical transceiver chip; the present invention adopts a plurality of micro-ring modulators to convert electrical signals into optical signals for information transmission, and realizes a secondary filtering function in combination with a micro-ring filter at a receiving part, and can reduce the crosstalk problem between two adjacent optical information transmission channels; the present invention realizes the receiving function by performing photoelectric conversion through a single-input photoelectric detector, and the transmitting end respectively inputs different wavelengths through four grating input interfaces, performs electro-optical information conversion through a micro-ring modulator, and further performs wave combination through a symmetrical bidirectional angle multimode interference coupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention in use state.

[0019] Figure 2 It is a schematic diagram of the structure of the bidirectional symmetrical angle multi-mode interference coupler in the present invention.

[0020] Figure 3 It is a schematic diagram of the structure of the micro-ring modulator in the present invention.

[0021] Figure 4 It is a schematic diagram of the structure of the micro-ring filter in the present invention.

[0022] Figure 5 It is a cross-sectional view of a lateral pin structure in a single-input photodetector of the present invention.

[0023] Figure 6It is a top view of the lateral pin structure in the single-input photodetector of the present invention.

[0024] In the figure: Oblique-incidence grating coupler-101, symmetrical bidirectional angle multimode interference coupler-102, micro-ring modulator-103, micro-ring filter-104, single-input photodetector-105. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1-2 The embodiment of the present invention provides a silicon optical transceiver chip, including an oblique-incidence grating coupler 101, a symmetrical bidirectional angle multimode interference coupler 102, a micro-ring modulator 103, a micro-ring filter 104, and a single-input photodetector 105; The plurality of oblique-incidence grating couplers 101 are composed of a grating region and a mode spot converter. The grating etched portion is a portion where a light signal is obliquely incident into the grating coupling region through an optical fiber with a certain coupling inclination angle, and the light signal is converted into a single-mode condition through the multi-mode spot converter and transmitted into the optical waveguide, thereby realizing the input and output functions of the light signal. The symmetrical bidirectional angular multimode interference coupler 102 is composed of multiple mode spot converters and a single multimode waveguide structure. The overall structure of the symmetrical bidirectional angular multimode interference coupler 102 is formed by etching silicon to form a ridge waveguide, and the etched conical structure with a certain angle is symmetrically placed on both sides of the ridge waveguide through certain design rules.

[0027] In this embodiment, the symmetrical bidirectional angle multimode interference coupler 102 can perform wavelength division multiplexing demultiplexing / multiplexing functions of optical signals, and can simultaneously realize the wavelength division and combination functions of the optical transceiver chip. In the receiving part, it is combined with the micro-ring filter 104 to realize the secondary filtering function, which can greatly reduce the crosstalk problem between two adjacent channels.

[0028] In this embodiment, the multiple micro-ring modulators 103 and the multiple micro-ring filters 104 are similar in structure and are composed of a linear optical waveguide and a micro-ring resonant cavity. The micro-ring resonant cavity is usually a small circle or ellipse and can form an optical resonance effect.

[0029] Furthermore, the micro-ring modulator 103 is connected via the through-end of the device, and the ring resonator of the micro-ring modulator 103 has a PN carrier doping structure, the purpose of which is to adjust the effective refractive index and group refractive index in the waveguide by adding voltage to achieve the phase modulation of the optical signal.

[0030] More specifically, the micro-ring modulator 103 is connected to the download end of the micro-ring filter 104 to achieve a filtering effect, and is cascaded with the angle multi-mode interference coupler 102 to achieve a secondary filtering function, which can greatly reduce the crosstalk between two adjacent information channels, and finally connect multiple single-input photodetectors 105 for photoelectric conversion to achieve the optical information receiving function.

[0031] In this embodiment, please refer to Figure 2 , where R and T represent the wavelength of the receiving end and the wavelength of the transmitting end of the transceiver chip respectively, and the receiving end of the symmetrical bidirectional angle multimode interference coupler 102 is input by multiple wavelengths, namely λ1, λ2, λ3, and λ4, and is input into the multimode waveguide region through a single-port pattern spot converter with an inclined angle of the angle multimode interference coupler, and wavelength division is performed according to the dispersion self-image principle of the multimode waveguide region, and the pattern spot converter at the diagonal angle is output to achieve filtering; To be more specific, the receiving end of the symmetrical bidirectional angle multimode interference coupler 102 is input into the multimode waveguide area by multiple mode spot converters with tilted angles, multiplexed through the multimode waveguide area, and then output by a single oblique incident mode spot converter at a diagonal angle. The optical signals at the receiving end and the transmitting end are transmitted through the same symmetrical bidirectional angle multimode interference coupler 102, which not only improves the information transmission efficiency, but also greatly reduces the overall layout area of ​​the system.

[0032] The microring modulator 103 and the microring filter 104 are mainly related to the transmission spectrum change of the microring resonant cavity. The transmittance T can be expressed as:

[0033] Where t is the coupling coefficient between the optical waveguide and the microring, β is the propagation constant of light in the microring, which is related to the wavelength λ. When the voltage V is applied, the refractive index n of the microring will change, causing the propagation constant β to change. Specifically, the change in refractive index can be expressed as: in is the refractive index of the material and V is the applied voltage:

[0034] This change will cause the resonant wavelength Offset occurs:

[0035] This wavelength shift will cause a change in the transmission spectrum of the micro-ring modulator 103, thereby achieving modulation of the optical signal.

[0036] In this embodiment, please refer to Figure 3-4 The microring modulator 103 includes a microring resonator, input and output waveguides and electrodes. The microring resonator is ring-shaped and has specific resonance characteristics. When the optical signal enters the microring through the input waveguide, if the wavelength of the optical signal matches the resonance wavelength of the microring, the signal of the wavelength will be enhanced. The modulation part has P+ and N+ carrier doping to form a PN node. By applying voltage to the electrode, the effective refractive index of the microring can be changed, thereby modulating the intensity of the output signal.

[0037] Furthermore, the microring filter 104 is mainly used to selectively filter optical signals of a specific wavelength. Its structure is similar to that of the microring modulator 103, but it usually does not include electrodes. The microring filter 104 relies on resonance phenomenon and coupling design to achieve selective transmission of a specific wavelength by adjusting the shape, size or coupling mode of the microring. When the input optical signal passes through the microring, only the light matching the resonant wavelength of the microring can pass through the output waveguide, while the light of other wavelengths is suppressed. The microring filter 104 structure has optical waveguides on the upper and lower sides, which are the straight-through end and the download end respectively. The waveguide connected to the symmetrical bidirectional angle multimode interference coupler 102 at one end is used as the straight-through end, and the other end is used as the download end, which is connected to the single input photodetector 105 for photoelectric conversion.

[0038] In this embodiment, please refer to Figure 5-6 The single-input photodetector 105 is composed of a silicon-based single-mode optical waveguide and a conical mode spot converter on the left, with a wider ridge waveguide sandwiched in the middle. A layer of germanium waveguide is grown on the ridge waveguide, and P+ and N+ are doped on the germanium waveguide with a spacing of Wi. Metal G and S metal electrodes are made in the doping area respectively. The intrinsic region width Wi of the lateral pin structure can be adjusted by controlling the spacing between P+ and N+, and the detector speed can be adjusted to the maximum by optimizing Wi.

[0039] By adopting the above technical solution, a single symmetrical bidirectional angular multimode interference coupler 102 is used to realize wavelength division multiplexing and demultiplexing functions at the receiving and transmitting ends, and effectively avoid crosstalk between the two systems, while significantly improving the integration level and reducing the wafer production cost. By cascading the micro-ring filter 104 and the symmetrical bidirectional angular multimode interference coupler 102, secondary filtering can be achieved, which greatly reduces the crosstalk problem between two adjacent information channels. The micro-ring modulator 103 has the advantages of small size and high speed, and to a certain extent meets the needs of most transmitting chips on the market.

[0040] In this embodiment, the oblique-incidence grating coupler 101 is made of silicon-based materials and can couple input and output of optical signals.

[0041] In this embodiment, the symmetrical bidirectional angular multimode interference coupler 102 is composed of ten conical mode spot converters with a certain angle and a multimode waveguide according to certain design rules, which are used to realize effective wavelength selection function, and the symmetrical bidirectional angular multimode interference coupler 102 can realize the multiplexing and demultiplexing functions of two wavelength division multiplexing on the same device. Part of this function can be used for the receiving part of the transceiver chip, and the other part can be used for the transmitting part of the transceiver chip. The crosstalk between the transceiver functions can be reduced to an extremely low level.

[0042] In this embodiment, the micro-ring modulator 103 is composed of a ring waveguide structure and a single-mode waveguide coupled to each other. The ring structure is doped, and the plasma dispersion effect can make the doped carriers move under the action of the electric field to achieve the modulation function of the optical signal.

[0043] Specifically, the symmetrical bidirectional angular multimode interference coupler 102 optical wavelength division multiplexing device interacts with the microring filter 104 to not only realize the wavelength division multiplexing function, but also greatly reduce the crosstalk problem between the optical signals of two adjacent channels.

[0044] Furthermore, the micro-ring filter 104 is composed of a ring waveguide structure and two single-mode waveguides coupled to each other, and the filtering function is achieved by the resonance of the micro-ring.

[0045] In this embodiment, the transceiver chip uses a single symmetrical bidirectional angular multimode interference coupler 102 to simultaneously implement wavelength division multiplexing functions of the receiving end and the transmitting end, which greatly increases the utilization rate of the chip area.

[0046] The working principle of the present invention is: when in use, the symmetrical bidirectional angle multimode interference coupler 102 is composed of ten tapered mode spot converters with a certain angle and a multimode waveguide according to certain design rules, which is used to realize an effective wavelength selection function, and the device can realize the multiplexing and demultiplexing functions of two wavelength division multiplexing on the same device. Part of this function can be used for the receiving part of the transceiver chip, and the other part can be used for the transmitting part of the transceiver chip. The crosstalk between the transceiver functions can be reduced to an extremely low level. The transceiver chip uses a single symmetrical bidirectional angle multimode interference coupler 102 to simultaneously realize the wavelength division multiplexing functions of the receiving end and the transmitting end, which is extremely The utilization rate of the chip area is greatly increased. The receiving end receives the optical signal through a single grating input interface, which is connected to the symmetrical bidirectional angular multimode interference coupler 102 for filtering. The output interface is connected to the micro-ring filter 104 for secondary filtering, which can effectively reduce the crosstalk between two adjacent output channels. Then, the single-input photodetector 105 performs photoelectric conversion to achieve the receiving function. The transmitting end inputs different wavelengths through four grating input interfaces respectively, and performs electro-optical information conversion through the micro-ring modulator 103, and then combines the waves through the symmetrical bidirectional angular multimode interference coupler 102, and finally outputs them through a single grating interface to achieve the transmitting function.

[0047] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0048] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A silicon photonic transceiver chip, characterized in that: It comprises an oblique-incident grating coupler (101), a symmetrical bidirectional angle multimode interference coupler (102), a micro-ring modulator (103), a micro-ring filter (104), and a single-input photodetector (105), wherein a plurality of the oblique-incident grating couplers (101) are composed of a grating region and a mode spot converter; The symmetrical bidirectional angular multimode interference coupler (102) is composed of a plurality of mode spot converters and a single multimode waveguide structure. The overall structure of the symmetrical bidirectional angular multimode interference coupler (102) is formed by etching silicon to form a ridge waveguide, and the etched conical structure with a certain angle is symmetrically placed on both sides of the ridge waveguide according to certain design rules.

2. The silicon photonic transceiver chip according to claim 1, characterized in that: The micro-ring modulators (103) and micro-ring filters (104) are similar in structure and are composed of a linear optical waveguide and a micro-ring resonant cavity. The micro-ring resonant cavity is usually a small circle or ellipse.

3. The silicon photonic transceiver chip according to claim 2, characterized in that: The micro-ring modulator (103) is connected via a through-end of the device, a PN carrier doping structure is provided in the ring resonant cavity of the micro-ring modulator (103), and the micro-ring modulator (103) is connected to a download end of a micro-ring filter (104).

4. The silicon photonic transceiver chip according to claim 1, characterized in that: The receiving end of the symmetrical bidirectional angular multimode interference coupler (102) is inputted with multiple wavelengths, namely λ1, λ2, λ3 and λ4, through a single-port pattern spot converter with an inclined angle of the angular multimode interference coupler (102) to input into the multimode waveguide region, performs wavelength division according to the dispersion self-imaging principle of the multimode waveguide region, and outputs through the diagonal pattern spot converter.

5. The silicon photonic transceiver chip according to claim 4, characterized in that: The receiving end of the symmetrical bidirectional angular multimode interference coupler (102) is input into the multimode waveguide region by a plurality of mode spot converters with tilted angles, multiplexed through the multimode waveguide region, and then output by a single oblique incident mode spot converter at a diagonal angle. The optical signals at the receiving end and the transmitting end are transmitted through the same bidirectional symmetrical angular multimode interference coupler.

6. The silicon photonic transceiver chip according to claim 3, characterized in that: The micro-ring modulator (103) comprises a micro-ring resonator, input and output waveguides and electrodes; the micro-ring resonator is ring-shaped, and a modulation portion has P+ and N+ carrier doping to form a PN node.

7. The silicon photonic transceiver chip according to claim 3, characterized in that: The microring filter (104) is similar in structure to the microring modulator (103), but generally does not include electrodes. The microring filter (104) relies on resonance phenomena and coupling design; The micro-ring filter (104) structure has optical waveguides at the top and bottom, which are respectively a straight-through end and a download end. The waveguide connected to the bidirectional symmetrical angle multimode interference coupler (102) at one end is used as the straight-through end, and the other end is used as the download end, which is connected to a single-input photodetector (105) for photoelectric conversion.

8. The silicon photonic transceiver chip according to claim 1, characterized in that: The single-input photodetector (105) is composed of a silicon-based single-mode optical waveguide and a conical spot converter on the left, with a wider ridge waveguide sandwiched in the middle. A layer of germanium waveguide is grown on the ridge waveguide, and P+ and N+ doping are performed on the germanium waveguide with an interval of Wi width. Metal G and S metal electrodes are respectively made in the doped area.

9. The silicon photonic transceiver chip according to claim 1, characterized in that: The microring modulator (103) and the microring filter (104) are mainly related to the transmission spectrum change of the microring resonant cavity. The transmittance T can be expressed as: Where t is the coupling coefficient between the optical waveguide and the microring, β is the propagation constant of light in the microring, which is related to the wavelength λ. When the voltage V is applied, the refractive index n of the microring will change, causing the propagation constant β to change. Specifically, the change in refractive index can be expressed as: in is the refractive index of the material and V is the applied voltage: This change will cause the resonant wavelength Offset occurs: This wavelength shift will cause a change in the transmission spectrum of the micro-ring modulator (103), thereby achieving modulation of the optical signal.

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